Optical profile grinding machine



July 8, 1941. N M, WQHLFARTH 2,248,446

OPTICAL PROFILE GRINDING MACHINE I Filed June 10, 1939 2 Sheets-Sheet 1H Q 3/4, 23 a E Rez'nhardMaxWohlfafih I 25 26 ByIhZfSAHOIneyQ m It July8, .1941. R. M. WOHLFARTH OPTICAL PROFILE GRINDING MACHINE 2Sheets-Sheet 2 Filed June I 10, 1939 I !I{ IIIIIIIIAVIIIIIIIIlIIIIIIIlIlIIIIIIl A RezhhardMcLx 4414,44

' By his Afiorney ments are used it can happen that thelines oithe slideorturntable used as a frame is mounted shadow are distorted. Furthermorethe exactthe upper part of a microscope and also the up- Y of thepicture on the screen mustbe done b'yithe sit-ions so that either theupper part of the ml- Patented July 8, lgdl STATE OPTICAL PRO GRINDINGMAC i i Reinhard Max Wohlfarth, Dresden, Germany, as-

signor to Aktiengesellschaft vorm. Seidel 8: Naumarm, Dresden, GermanyApplication June 10; 1939, Serial No. 278,397 I in Germany June 29, 1938'6 Claims. (oral-165) The present invention refers to an opticalvpro-This adjustment is of extreme importance befile grinding machine onwhich form-gauges and cause an enlargement on the screen is obtainedform-tools, etc, are ground by causing a grlndonly in the position ofthe sharpest adjustment. ing-disk to grind the form-gauges or form-toolswhich enlargement corresponds to the profile line to their actual shapeswhich shapes are repredrawn in enlargement on the screen. And theresented by the lines of a very much enlarged drawremains Still the lack oGleam-9 8. due to the ing. a. fusion of the screen. i

Generally we distinguish between two of If the kind of optical profilegrinding machine optical profile grinding machines. In the first fittedwith microscope as its optical system asthe pattern line is traced pieceby piece by means 10 sures absolute exactness of the making of the of apin; and this motion is transferred by means profile when the grind n sdo e fairly .S O y, of a pantograpli to an optical system which serveseven if the adjustment of, the microscope is not forwatching the pieceto be ground at the grindmade with the greatest exactness, then thegrinding point. The axis or the optical system is al i p e s in the d ofOptical profile crimiways brought to the exact position above-the 5 mmachine fitted with projection apparatuses grinding point and thegrinding wheel is guided s optical system procee P p Somewhat so that itgrinds to that place or point which is faster, but at the expense ofabsolute exactness. observed by means of the optical system. Here- The pe invention bring-S forth anblitifial tofore the optical system has beenin the form of profile grinding machine in which are incorpo amicroscope. lithe tracing of the pattern is rated the advantages ofobservation by both finds done with great exactness, which can be satisQf p y while the dlsadvantagesare iactorily accomplished by means ofphototechnic avoided, i. e. the rather slow work .under ohse rvamethods, this foregoing method guarantees I an I tion by microscope andthe less exact work made. absolute exactness in the profiles to beground O s o by P j o aPP J dependent upon the accuracy of thepantograph In my invention, I am using an optical profile mechanism. Theoptical enlargement .of the g in machine i which the axis of an Opticalmicroscope does not directly aiiect the exactness syste p ss d along atraces the desired Shape of the operation at the point of grinding. Itof the form-gauge or form-tool under the serves only to observe thepoint of grinding. 1 guidance oi a mechanical device, which is made Inthe second kind of optical profile grinding to follow a drawn pattern. vmachine the outline of the entire iorm-gauge .or In order to accomplishthe aboveprocess it is form-tool to be ground is projected on a screenthe first object o y invention o P de fi e in shape of a picture. Onthis screen the profilesaid machine 4 with means to observe the Pointlines are drawn inan enlarged scale and the proo grinding y Optical Pojection. .Fo h D jected picture of the form-gauge or form-tool can poseI use an illuminating device Of- 8 7 be compared with the profile-linesdrawn in fen-1 t i y f li ht, the rays of which psss throush largement.Here one sees as a shadow onj'the a set of Optica l s p p l t P 9screen,.even if vanishing at times, thegrinding screen- Q 5" wheel whichis operating on the iorm gapgeor A".s'ec 0nd object of my invention isto provide form-tool in a steady vertical up and down; mo- 40 the saidmachine with. a. new and useful device, tion, and therefore it'ispossible to follow up the which allows observation of a give P operatingof the grindingwheel on the form-gauge grinding by means. of two kinds,of Optical. 5 or form-tool and to continue the grinding until tems, i.e. observation by microscope or observathe outlines of the picturecoincide with the protion by means of optical projection, each kind offile lines drawn on the screen. observation being used independently ofthe other Since in this second method optical enlargeat the choice of'the operator. Therefore on a nessof the method depends on how carefullythe per set 9f lensesof the apparatus for optical prooperator servicesthe machine; ,The adjustment jectlon. This Iramecan be shifted into twopooperator so that theoutlines of "the picture ap croscope'pr the upperset of the lenses of the pear sharp and clear-at all times. {Thisadju'st apparatus for the optical projection device (which ment'howeverdep n s .more orless on the good .'eve1 ;is desired). .can rest over thelower partiotv eyesight of the operator. r 5 the'ontical sv'stem.

Other objects of my invention are explained as they occur in thefollowing description and in the drawings appended.

In the drawings V Fig. 1 shows a front view of an optical profilegrinding machine equipped with means for observation by projection,

Fig. 2 shows a view from above of Fig. 1,

Fig.3 shows a section of the optical system in the pantograph mountingand a view of. the projection device,

Fig. 4 shows a section of two upper parts of the optical system mountedon a gangway,

Fig. 5 shows a view from above of the pantograph system and of aturntable with two upper parts of the optical system.

On base Ii there is a structure on which th form-gauge or form-tool isplaced. This structure consists of a housing I2 which is fastened to thebase and in which is a bevel wheel l3.

This wheel can be turned by means of a second bevel wheel I4, which isfastened to the end of a shaft [5. To the other end of the shaft 1 5 isfastened a hand wheel IS. The bevel wheel I3 is connected with aninternally threaded cylinder l1. This cylinder when turned by means ofthe hand wheel i6 screws a spindle 18 up and down which spindle supportsa hollow shaft l9. This shaft moves within the stationary housing 20. Onthe upper end of the shaft l9 there is a slide .2! which can be moved tothe right or left by means of a spindle 2'2 and a crank 23. Across theslide 2| there is another slide 24 with a table 24a. This slide 24 withthe table 24a can be moved to and fro by means of a spindle 25 and acrank 26. The form-gauge or form-tool '21, to be ground can be clampedon top of the said table 24a. s i

Facing this structure there is a construction on which the grinding-diskis movably mounted.

This construction consists of the following parts:

On the base i I is a stationary platform 28. On this platform 28 isrotatably mounted a gangway 29ion which moves a slide 30 to and fro.This slide 30 is moved by means of a spindle 30a and crank 30b. Acrossthe slide 3|] there is another slide 3| which slide moves by means of aspindle 3m and a crank 3lb. .Upon this slide 3| there is a housing 32for the gears. At the rear of this gear box 32 there is adriving.mechanism, for instance an electromotor 32a which drives the grindingdisk 33. This grinding disk 33 is mounted on a slide 34 which slide ismounted movably on the front of an arc-like frame 35 and travels up anddown by means of a leverdevice (not shown). The gangway 29 and itssuper-structure, i. e. the gear-box 32' and the arc-like frame 35 andthe slides 3Ufand 3| and the grinding-disk 33 can be turned around onthe stationary platform 28 by means of a spindle 36.

Projecting from the side of the base ll there is an arm 31 supporting astand 33. On top of this stand 38 is a drawing board 39 on which adrawing 40 is stretched. This drawing 40 shows the shape 40a of theprofile to be ground on a very much enlarged scale.

From the base Ii extends upwards a column device which when moved alongthe lines of the pattern-drawing, produces a similar motion of the axisof the optical system. This pantograph system consists of a short arm 43parallel to a long arm 44 and of two parallel connecting rods 45 and 46.In the free end of the rectangular arm 42 is a hole into which ismovably fitted an outer bushing 41. To the top of this outer bushing 4'!is fastened the connecting rod 46. Within the outer bushing 41, butexcentrically to its center, there is movably fitted an inner bushing 48to which is fastened the short arm 43. 'This short arm 43 is connectedwith the long arm 44 by the connecting rod 45. Excentrically to thecenter of the inner bushing 48 there is a hole into which is fitted alower set 49 of an optical system containing the objective lenses. Theend of the long arm 44 is provided with a device 50 which traces thecontours of the drawing. Over the hole in the bushing 48 is a projectiondevice. This device consists of a frame 5! which carries a set ofprojection lenses 52, a mirror'53 and a plane or screen 54 upon which toproject. It is an advantage to have the projection device provided withan attachment 65 for a magnifying glass.. In order to have no lightentering from the outside upon the projection device the latter iscovered by a casing 56.

The optical profile grinding machine has two illuminating devices. Oneof them is within the base II. It consists of a source of illumination51 and above it a set of lenses 58. These lenses concentrate the raysupon the point of grinding from below and produces a deep shadow on thescreen or projection plane 54.

Another illuminating device is attached to the lower side of therectangular arm 42. It consists of one or more sources ofillumination 59which throw their rays upon the upper side of the formtool orform-gauge. The collected rays of this device are .of such intensitythat they reflect towards the optical system and then produce aprojection of the form-gauge or form-tool at the screen or plane.

The machine functions as follows:

After having clamped the form-tool or formgauge on the work-table 39 andafter having stretched the drawing of the pattern desired on the drawingboard 34, the tracing device 50 on the end of the long arm 45 of thepantograph is moved from a starting point to a further point to beground. The pantograph system moves the axis of the optical system tothat point of it to which the work-piece is to be ground, in other wordsthe axis of the optical system marks the position of the point to whichthe form-tool or form-gauge is to be ground. This point is observedsimultaneously by means of the projection device. On the screen orprojecting plane this fixed point and the central point of the image areone. It can be marked by a reticule drawn upon the screen or the fixedpoint can appear projected on the screen or plane. The point of thepattern line traced by means of the tracing device at the free end ofthe long pantograph-arm, and the actual point on the form-tool orform-gauge fixed by the optical axis,-and the central-point of the imageon the screenthese three coincide. Now, by illumihating the form-gaugeor'form-tool from below or from above the image of the unfinishedformgauge or form-tool extends beyond the central point on the screen,and this part which extends must be ground away. For this purpose the 4grinding disk while rotating moves up and down and must .begraduallymoved in against the edge cranks until it has ground ofi theextending parts of the'form-gauge or form-tool, i. e. until the 'aaaaeeofinished point ofthe workpiece coincides with the fixed point on thescreen. Then a further point of the pattern is traced and this processis repeated. In this way the optical axis strikes each time a point onthe form-gauge or form tool which lies besides the last one ground untilthe repeated grinding operation has finished the desired workpiece.

'The ratio of the enlargement of the image on the screen is about 20 to1; that is to say, the

area shown as silhouette on the projection plane is about 20-timesgreater than the area covered by the objective lenses of the opticalsystem. Observation on such an enlargement does not I always satisfy thedemands of required exactness.

48 is constructed as a gangway 61 for a slide 62 which slide is used asa frame to carry two upper parts of the optical system consisting of anupper set of lenses 63 of a microscope at one end of the frame and. alsoa set of lenses 64 with mirror 65 to complete the device of a projectionapparatus on the other end of the frame. On the gangway ii are two stops6G and 61 to limit the scope of motion of the slide. If the end of theslide 62 which carries the set of lenses 64 with mirror 65 is moved overthe lower part of the optical system until it strikes the stop 66,theprojection apparatus is completed, and the spot 1 to be ground may beobserved as silhouette on the projection plane. The distance of theplane from the mirror 65 can be adjusted in order to produce sharp andclear images. The slide when in the position to complete the projectionapparatus is arrested by means of a tapered pin 68 which passes throughthe hole 62a in the slide 62 into a hole 10 of the gangway 6|.

If the end of the slide 62, which carries the upper set of lenses 63 ofthe microscope is moved over the lower part 60 of the optical systemuntil it strikes the stop 61 the microscope. system of observation iscompleted. For this purpose withdraw the pin 68 from the hole 10 andmove the slide 62 till it strikes the stop G'I'and insert the pin 68through hole 62a into hole 69. The microscope part for observation nowrests over the lower part 60 of the optical system (see Fig. 4), and thespot to be ground may be observed by means of the microscope. 4

Instead of using aslide 62 as a frame on which the upper parts 63 and64-65 are mounted, a turntable 13 may be used.. This design is shown inFig. 5. The upper end of the inner bushing has been shaped into a flangeand united into one piece with the short arm 15. A bolt 14 is screwedinto this flange acting as a pivot around which the turntable isrotatorily mounted. This turntable 1-3 carries the said two upper partsof the optical system, namely: an upper set of lenses [6 to complete themicroscope. and a set of lenses 'I'I with mirror 18 to complete theprojection apparatus. is mounted on an are or. circle, the axis of whichlies in the center of the bolt 14. By turning the turntable 13 eitherthe upper part of the micro- Each of the two upper parts.

scope or the upper part of the projection ap-.

paratus completes with the lower part of the optical system 60 thedesired means of observation.

Two stops I9 and 80 will halt the turntable I3 in its desired positionfor observation and this position can be secured by means of a taperedpin 8| in much the same way as is used in case of the slide.

The work with an optical profile grinding machine fitted with the dualsystem of observation describedabove is as follows:

The mechanical operation of the machine is the same as is describedabove in the machine with only the projection device. However theobservation of the grinding process can be made either by means of theprojection apparatus or by means of the microscope. If the projectionapparatus is desired the frame supporting the two upper parts of theoptical system is brought in the position where the set of lenses withthe mirror complete the projection device. Then the silhouette of thepoint to be ground is projected on the plane or screen and the operatormay observe it while grinding the spot to within a fraction of thedesired point to be reached. In order to observe the grinding processfrom now on with a greater exactness the operator shifts the frame whichsupports the two upper parts of the optical system in the position wherethe upper set of lenses complete the microscope. The observation of thegrinding process can be observed from this point on with a greaterexactness because the ratio of the enlargement of the microscope entlyare avoided.

I claim: 1. An optical profile grinding machine for the grinding ofform-gauges or form-tools said ma.-

the grinding-disk on the form-tool or form-gauge and apparatus tocomplete the means to observe in enlargement point by point the path ofthe grinding-disk.

2. An optical profile grinding machine'for the grinding of form-gaugesor form-tools said machine consisting of a base, a structure on whichthe form-gauge or form-tool is clamped, a construction facing thisstructure on which the grinding-disk is movably mounted, a drawingboardon which may be stretched an enlarged pattern-drawing, a long arm and ashort arm and two connecting rods, forming a pantographsystem, a tracingdevice at the free end of the long arm for tracing point by point thelines on the pattern drawing. and a set of lenses mounted into the shortarm of the pantograph and forming the lower part of an optical systemfor observing the path of the grinding-disk on the formtool orform-gauge, an upper part of a. projection apparatus which completes theoptical system and which under enlargement allows ob-- servation pointby point of the path of the grinding-disk and illumination devices toilluminate the point of grinding.

3. An optical profile grinding machine for the grinding of form-gaugesor form-tools said machine consisting of a base, a structure on whichthe form-gauge or form-tool is clamped, a construction facing thisstructure on which the grinding-disk is movably mounted, a drawingboardon which may be stretched an enlarged pattern-drawing, a long arm and ashort arm and two connecting rods, forming a pantographsystem, a tracingdevice at the free end of the long arm, for tracing point by point thelines on the pattern-drawing, and a set of lenses mounted into the shortarm of the pantograph and forming the lower part of an optical systemfor observing the path of the grinding-disk on the form-tool orform-gauge, a, set of lenses and a mirror, and a projection plane and aframewhich carries these lenses, mirror and projection plane as theupper part of the optical system which upper parts complete with thelower part of the optical system a projection apparatus which underenlargement allows observation point by point of the path of thegrinding-disk and sources of illumination to illuminate the point ofgrinding both from above and from below.

4. An optical profile grinding machine for the grinding of form-gaugesor form-tools, said machine consisting of abase, a structure on whichthe form-gauge or form-tool is clamped, a construction facing thisstructure on which the grinding-disk is movably mounted, a drawingboardon which may be stretched an enlarged pattern-drawing, a system having atracing-device for tracing point by point the lines on thepattern-drawing, a set of lenses forming the lower part of means forobserving the path of the grinding-disk on the form-tool or form-gaugeand a dual device for observation of the point of grinding, having oneupper set of lenses which with the lower set of lenses, complete amicroscope, and a second upper set of lenses which, with the lower setof lenses, complete a projection apparatus, and illumination-devices forilluminating the point of grinding.

5. An optical profile grinding machine for the grinding of form-gaugesor form-tools said machine consisting of a base, a structure on whichthe form-gauge or form-tool is clamped, a construction facing thisstructure on 'which the grinding-disk is movably mounted, a drawingboardon which an enlarged pattern-drawing may be stretched, an em fastened atright angle mounted into the free end of this arm, an inner bushingrotatably mounted within the outer bushing, a pantograph systemconsisting of a short arm, fastened on top of the inner bushing, a firstconnecting rod linked on the free end of the short arm, a secondconnecting rod, fastened on top of the said outer bushing and parallelto the first connecting rod, and a. long arm linked to the free ends ofthe connecting rods and parallel to the short arm, a tracing-devicemounted on the free end of the long arm of said pantograph-system, and aset of lenses mounted into the short arm of the pantograph and formingthe lower part of means to watch the path of the grinding-disk on theform-tool or formgauge, a gangway constructed on top of the innerbushing, a .slide movably mounted on said gangway which slide carries atone end one upper set of lensesto complete a microscope and at the otherend a second upper set of lenses and a mirror and a-projection plane tocomplete a projection apparatus, means to limit the scope of motion ofsaid slide and sources of illumination for illuminating the point ofgrinding both from above and from below.

6. An optical profile grinding machine for the grinding of form-gaugesor form-tools said ma-- chine consisting of a base, a structure on whichthe form-gauge or form-tool is clamped, a construction facing thisstructure on which the grinding-disk is movably mounted, a drawing-boardon which may be stretched an enlarged patterndrawing, an arm fastened atright angle on top of the column, an outer bushing rotatably mountedinto the free endot' this arm, a pantograph system consisting of a shortarm which short arm is a part of a. flange at the upper end of an innerbushing which inner bushing is rotatably mounted within the outerbushing, a first connecting rod linked on the free end of the short arm,a second connecting rod fastened on top of the said outer bushing andparallel to the first connecting rod and a long arm linked to the free.ends of the connecting rods and parallel to the short arm, atracing-device mounted on the free end of the long arm of saidpantograph system, and a set of lenses mounted into the short arm of thepantograph forming the lower part of means to watch the path of thegrinding-disk on the form-tool or form-gauge, a turn-table rotatablymounted around a bolt over the flange at the upper end of the innerbushing of the pantograph, which tum-table carries one upper set oflenses to complete amicroscope and a. second upper set of lenses and amirror and a projection plane with reticule to complete a projectionapparatus, means to limit the scope of motion of said slide, and sourcesof illumination for illuminating the point of grinding both from aboveand from below.

REINHARD MAX WOHLFAR'IH.

